diff options
| author | Shawn Nematbakhsh <shawnn@chromium.org> | 2016-09-08 09:56:47 -0700 |
|---|---|---|
| committer | chrome-bot <chrome-bot@chromium.org> | 2016-09-08 17:57:57 -0700 |
| commit | 946921a974542b9e00fa412ae03df59f8fa82d84 (patch) | |
| tree | 9e3ccd00249a240765e94eeae06c6b2016879f6b | |
| parent | df80ec22ca2aa67e3e70eeb987e20fcd870341fe (diff) | |
| download | chrome-ec-946921a974542b9e00fa412ae03df59f8fa82d84.tar.gz | |
npcx: rtc: Write RTC reg twice to ensure non-volatility
TTC must be written twice, otherwise the value will be lost on EC reset,
even if VBAT stays stable.
BUG=chrome-os-partner:57010
BRANCH=None
TEST=On kevin, run 'rtc set 55555' then trigger cold reset through
servo. Run 'rtc' on subsequent boot and verify timing ticks did not
reset to zero.
Change-Id: If05b698e75eece5f8879a109b98886b547eb71a4
Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/382654
Commit-Ready: Shawn N <shawnn@chromium.org>
Tested-by: Shawn N <shawnn@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
| -rw-r--r-- | chip/npcx/system.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/chip/npcx/system.c b/chip/npcx/system.c index f6f4804c35..babfbe15a3 100644 --- a/chip/npcx/system.c +++ b/chip/npcx/system.c @@ -26,8 +26,8 @@ #define HIBERNATE_WAKE_MTC (1 << 0) /* MTC alarm */ #define HIBERNATE_WAKE_PIN (1 << 1) /* Wake pin */ -/* equivalent to 250us according to 48MHz core clock */ -#define MTC_TTC_LOAD_DELAY 1500 +/* Delay after writing TTC for value to latch */ +#define MTC_TTC_LOAD_DELAY_US 250 #define MTC_ALARM_MASK ((1 << 25) - 1) #define MTC_WUI_GROUP MIWU_GROUP_4 #define MTC_WUI_MASK MASK_PIN7 @@ -141,14 +141,14 @@ uint32_t system_get_rtc_sec(void) void system_set_rtc(uint32_t seconds) { - volatile uint16_t __i; - - /* Set MTC counter unit:seconds */ + /* + * Set MTC counter unit:seconds, write twice to ensure values + * latch to NVMem. + */ NPCX_TTC = seconds; - - /* Wait till clock is readable */ - for (__i = 0; __i < MTC_TTC_LOAD_DELAY; ++__i) - ; + udelay(MTC_TTC_LOAD_DELAY_US); + NPCX_TTC = seconds; + udelay(MTC_TTC_LOAD_DELAY_US); } /* Check reset cause */ |